Line test methods are known which consist in applying logic signals to a first output pin of a first circuit and in recording the logic levels on the input pin of the second circuit that is connected to the first output pin. The logic levels measured on the input pin of the second component are compared to expected levels. If these levels differ, the line is considered to be defective. However, this type of method is costly because it requires heavy test equipment. In practice, it is necessary to incorporate in the line to be tested an element that makes it possible to generate the output logic signals, an element that makes it possible to measure the input logic level, and an element for synchronizing the input and output pins of the first and the second circuits so as to attribute the response from the input pin to a logic signal applied to the output pin. The expression “false alarm” is used to mean the detection of a failure of the line being tested when the line has not failed. The methods described previously present a high false alarm rate. It is indeed possible to detect a failure of the line that is actually due to a failure of one of the elements of the test equipment.